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Challenges making stab resistant garments

AgResearch’s new stab-resistant fabric combines wool fibre with a synthetic yarn that’s very difficult to cut. Senior Scientist Dr Stewart Collie explains why it is difficult to cut and shows how special electric shears perform the task that standard scissors can’t achieve.

Questions to consider:Considering the cut resistance of the yarn, what are some other situations where clothing made from this fabric would useful?

Dr Stewart Collie (AgResearchThere are some problems or some issues to do with cutting the fabric. You can imagine it’s meant to be cut resistant, so cutting out pattern pieces is a challenge. But in terms of sewing up, there is no problem at all.

The type of structure that we've got, this knit-based structure, is lots of loops so there are very small holes in the fabric already, so it’s relatively easy for a sharp tip to penetrate that fabric, and that is one of the limitations of its protective performance is that, if somebody was to try and stab you with a syringe, or something like that, then this type of fabric wouldn't be able to protect you. But it does mean that, when you're sewing, you can just sew it normally. The sewing needle will penetrate through the little holes – it will work its way through quite well.

But the yarn itself, in order to disrupt that, you've got to cut through yarns, and the molecular structure and chemical structure of the Vectran™ yarn is such that the polymer is extremely tough, and there are aspects of its molecular configuration and its chemistry that means that it’s very difficult to either break it or cut the material in half. And it’s almost like you're getting closer to a metal type of material in terms of its behaviour, although it’s still a flexible polymer. So you have something that is able to bend, but it’s got extremely high strength.

It’s very difficult to cut the fabric with a conventional pair of scissors, but a lot of the time in industry, there are people working with these sort of technical fabrics that have other types of cutting tools that they use – electrically powered ones – and there is various types of tools that have sort of got high-speed rotating blades that can get through this type of thing.